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Installing a Vacuum Breaker Backflow Prevention Device

I have vacuum breaker backflow prevention device and live in midwestern ND. It obviously freezes here.... I am considering installing the backflow prevention device inside my garage rather than outside. I have been told that they sometimes leak, but can deal with that since there is a drain very close to where I am looking at installing it. A local plumber told me that he thinks the valves main malfunction or failure is due to them not being properly drained or blown out and freezing.
Anyone have any opinions against or for installing this device inside, rather than outside?
Thanks
TeaMan

IF you attempt to install a PVB indoors, there's several things that you have to consider. For one, I believe there are additional code requirements usually step in and require the drain to handle a certain level of flow. This flow requirement is usually what a worst case senario would be, which is basically the same as if a pipe had burst. Search the history of this web site and you can find instances where these PVB have not just leaked but forcefully spewed huge quanities of water. You got to be able to handle the quanity, as well as the direction of where all this water might go.

Then on top of that, you have to consider service. Even if you plan on servicing the system yourself, perhaps the next home owner isn't. It's much more difficult for an irrigation contrator to deal with a system when the backflow preventor in indoors rather than readilly accessable outdoors.

There are just a few of the REASONS for Wet Boots answer.

If your worry is the PVB freezing, you should be able to install it with unions so that when it comes time to winterize the system, you simply remove the PVB and store it indoors. If you go this route, get an extra set of union pieces so that you can attatch dead-end nipples over the ends of the pipe while the PVB is removed (avoid insects taking up residence in your pipe during the winter).

Installation advice

Thanks for the advice guys.
OK, makes sense to put it outdoors. I like the idea of unions to remove it. It will need to be mounted on the south west side of the house and will be in direct sunlight. I know PVC degrades in UV light. What do you recommend to use to get up to the device and back down to the manifold? I've heard of painting the PVC to ensure it handles UV light but am not sure what kind of paint bonds to PVC. I have to go pretty high on the house to get it above the highest head. Almost 4', this was another reason I was looking to put it indoors. Hide it in a sense rather than having it hanging on the side of the house. Point here is, it's more than a few inches of pipe to protect from UV light.
Any advice on this?

RPZ devices

It appears that I need an RPZ device anyway. Glad I asked a few questions. I will have two supplies, one from a holding tank that collects rain water, and the other the municipal system. I need a device that will prevent backflow pressure as well as siphoning. Any recommendations on which to use. I don't want to break the bank, but want something familiar and easy to maintain. I saw three brands in Sprinkler Warehouse, Febco, Conbraco and Wilkins. It's a 1" main line coming from the meter and to the meter for all that's worth.
I did find something very interesting reading up on them in their installation instructions. For all three, they say not to install them outside in areas that freeze. They said freezing conditions will damage the devices. All say to install inside and pipe to a drain in areas that freeze. Now, I'm not sure what to do. I realize it will be winterized and drained, but it doesn't mention this. They seem pretty strict on it.
TeaMan

I install RPZs outdoors, and they stay in place, even in sub-zero temperatures. Of course, all the water is removed from these devices prior to winter. Unfortunately, that removal requires partial disassembly of the RPZ. Follow mfr directions and you will be fine.

There are two models of RPZ that appear to be able to be winterized with a small (warm, but not hot, air temperature) compressor right through the device. One is the Watts 009, and I use those. The other is one I don't have experience with, and that is the Conbraco. What gives the Conbraco RPZ this appearance is the upward orientation of the check valves, and the lower-down location of one of the testcocks, needed to drain the lower portion of the device. (just the same, the first time I winterize one of those, I will still do the necessary disassembly to confirm that all the water is out)

To protect the PVC above ground, you can paint it to help reduce the effects of UV light. But even better would be to transition from PVC underground to copper above ground. Obviously the copper is impervious to UV light, and you're unliking the crack the copper should you ever hit it with a weed-eater.

All it takes is a PVC male and copper female and make place these joints under ground. You could even build "feet" into the copper pipe to support the backflow device without the risk of it getting knocked over and damaging the underground plumbing.

The attatched image is a CRUDE drawing of how you could build feet. In the drawing, the small tubing at the ends represents the PVC. The larger tubing represents the copper, and the box represents the backflow device (RPZ or PVB).